(a) Field of the Invention
The present invention relates to a method of preparing a negative active material for a non-aqueous electrolyte rechargeable battery and a negative active material for a non-aqueous electrolyte rechargeable battery prepared thereby. More particularly, the present invention relates to a method of preparing a negative active material for a non-aqueous electrolyte rechargeable battery having high crystallinity, excellent charge and discharge characteristics at a high rate, and excellent charge and discharge cycle-life characteristics, and a negative active material for a non-aqueous electrolyte rechargeable battery prepared thereby.
(b) Description of the Related Art
As for a negative active material of a rechargeable lithium battery, various carbon-based materials such as artificial and natural graphite, hard carbon have been used, which can all intercalate and deintercalate lithium ions. In order to provide a high-capacity rechargeable battery, there have been efforts to improve utility of a carbon-based active material and charge density per electrode volume. However, capacity of the material is similar to a theoretical capacity (372 mAh/g) of graphite, and charge density improvement reaches a limit, and therefore it is difficult to provide a high-capacity battery using currently carbon materials.
Therefore, development of metal lithium or a silicon alloy material as a negative active material has been actively undertaken, but utilization of such materials is not yet implemented yet to large stress caused by electrode expansion and shrinkage.
Lithium vanadium oxide has been noted as a high-capacity material due to small stress caused by electrode expansion and shrinkage. However, this material occurs the change of oxide structure during charge and discharge, and shows a capacity decrease due to such structure degradation (Japanese Patent Laid-Open Publication No. 2003-68305).